JPS6013623B2 - Data transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a data transmission method for transmitting a plurality of pieces of data;
More specifically, it relates to a data transmission method for transmitting data on the usage of electricity, gas, water, etc. to a data collection station, and in particular, in addition to the data to be transmitted, a synchronization signal that determines cueing, A redundant signal is simultaneously transmitted to clearly distinguish this synchronization signal, thereby ensuring synchronization between the transmitting side (terminal side) and the receiving side (data collection station side).

When transmitting multiple pieces of data, the conventional method for synchronizing the sending and receiving sides is to use a 1-clear circuit to determine the beginning of data transmission.

{21 Method of sandwiching data with a start signal and an end signal.

etc. are being considered.

However, method '1' requires some form of auto-clear circuit to be provided on the transmitting side, and method [21] requires that the start signal and end signal be distinguished from the data signal. There were drawbacks such as the complexity of the code.

If auto clear is not used, it is uncertain at what point the transmitting side will start transmitting data, and therefore a synchronization signal is required to determine the cue, but data is transmitted serially with binary values of on and off. In some cases, it becomes difficult to distinguish between data signals and synchronization signals.

Therefore, it is conceivable to use a series of codes as a synchronization signal that cannot exist as a data signal, but in that case, it is necessary to have the synchronization signal and the data signal have the same configuration, and to make sure that they all have the same code. is the easiest to implement. (If implemented using a special code, counterfeiting would be complicated for both the sender and receiver). For example, when data is transmitted sequentially for each digit of usage of electricity, gas, tap water, etc., Figure 1A
As shown in , if all the synchronization signals are turned on, if there is an on signal as digit information at the end of the digit, it becomes easier to distinguish between the data signal and the synchronization signal. Therefore, as shown in Figure 1B, if a redundant code is provided before the synchronization signal and all the redundant codes are turned off,
Since the information before the synchronization signal is reliably off, the synchronization signal and the data signal can be reliably distinguished. The present invention was made based on the above principle, and the following is as follows.
This will be explained in detail with reference to the drawings.

FIG. 2 is a block diagram for explaining an embodiment of the data transmission system according to the present invention, and FIG. 3 is an electrical signal waveform diagram of the main part of FIG. electric power,
A terminal device for measuring the usage of water or gas, etc., a data collection station for collecting data from each terminal device, and 1, 12 are transmissions connecting terminal device 1 and data collection station 0. Line 10 is a clock pulse oscillator provided at the data collection station.

The clock pulse from this clock pulse oscillator 10 (
(see FIG. 3A), the vertical direction of the transistor Tr2,
The off-operation is controlled, and the output of the transistor Tr2 is supplied to the bases of the transistors To and O. Therefore, if you select terminal 1 at the data collection station now,
Transistors Tr2 and TQo are controlled by clock pulses from a clock pulse oscillator 10, and clock pulses synchronized with the clock pulses are supplied to the terminal 1 through transmission lines 1, 12. This clock pulse (see Figure 3C) is connected to a diode to prevent backflow.
(See Figure 3B) to create a power supply voltage for the terminal, and when the charging voltage of the capacitor Co reaches a predetermined value, the bit counter 20 and digit counter 2
1 is set. The initial values of the counters 20 and 21 at this time are undefined, and it is unclear from which set state they will start.
By sending a clock pulse from the data collection station, the first output of both counters is eventually set, diode D becomes conductive, and transistor Tr is activated. Therefore, subsequent clock pulses are supplied to V.
When supplied, the clock pulse flows through the photodiode DP and the transistor Tr, and the clock pulse flows through the bit counter 2.
01 clock pulse to the bit counter 20.
The digit counter 21 is incremented by one step when the clock pulse is input by lq (see period T in Fig. 3C).
(corresponds to the synchronization signal in Figure 1). Therefore, this time, the digit counter 21 selects the one-digit transistor Tr2, but at this time, in the illustrated state, the transistor T
Since no collector voltage is supplied to r2, the transistor Tr is not conductive. In this way, digit counter 2
After the first digit of 1 is selected, when a clock pulse Po is sent from the data collection station, the clock pulse Pc
operates to advance the bit counter 20 by one step, but at this time, as described above, the transistor Tr is in the off state, and the clock pulse Po is applied to the resistor R with a relatively large resistance value.
3, the voltage drop across the missing resistor is small.
The potential at point C is kept relatively high (Fig. 3 C, Qo
reference). In this way, after the bit counter 20 is incremented by one step, when the second clock pulse P, is connected,
At this time, since the collector voltage is supplied to the transistors T and others through the bit counter 20, the clock pulse flows through the photodiode Dp and the transistor Tr and advances the bit counter 20 by one step, but the voltage across the resistor R at this time The drop is large, and therefore the potential at point C becomes small as shown by Q in FIG. 3C. Next, when the second clock pulse P2 is applied, since the bit counter 20 has advanced to the third bit position, no collector voltage is supplied to the transistors T, etc.
Therefore, the transistor Tr is not conducting, and the level of the fin at point C does not decrease as much as when the bit counter 20 is outputting the second bit. Thereafter, clock pulses P3 to P9 are sequentially sent from the data collection station in the same way, and the bit counter 20 is incremented, but during this time, the transistor T
r, is not made conductive, and therefore, the potential at point C is lowered only once during the single-digit data reading period L, depending on the position of the single-digit coin point of the meter M. Therefore, if the timing at which the potential at point C becomes low level is monitored, it is possible to read the one-digit reading of the meter M.
Thereafter, 1-digit, 1-digit, and 1-digit data are read in the same manner. The output terminal after 1 of the digit counter 21 is a redundant code terminal, but this redundant code terminal is open as shown in the figure, so during this period, that is, after the redundant code terminal is selected. , until the bit counter 20 completes one cycle, the transistor Tr is not turned on, and therefore the redundant code shown in FIG. 1B can be obtained. As is clear from the above description, according to the present invention, digital on/off switching is possible without using auto clear or sandwiching data with complicated start and end signals. Data transmission can be performed easily and reliably using only signals.

[Brief explanation of drawings]

Fig. 1 is a time chart for explaining the operating principle of the present invention, Fig. 2 is a tortoise circuit diagram for explaining one embodiment of the present invention, and Fig. 3 is for explaining the operation of Fig. 2. FIG. 3 is an electrical signal waveform diagram for 10... Clock pulse oscillator, 20...
Bit counter, 21... digit counter, M... measuring instrument. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 Consists of a terminal device and a data collection station connected to the terminal device via two transmission lines, each of the measuring instruments in the terminal device is controlled by a clock pulse sent from the data collection station through the transmission line. In a data transmission method in which the contact positions of the digits are sequentially read and the read values are transmitted to the data collection station, the terminal device obtains the DC power supply voltage from the clock pulse sent from the data collection station. a bit counter scanned by a clock pulse sent from the data collection station; and a digit counter incremented each time the bit counter is incremented by a predetermined plurality of bits; By the clock pulse sent from the data collection station,
The bit counter, the contact position of each digit of the measuring instrument, and
The data consisting of the logical product of the digit counters is detected and transmitted to the data collection station, and the digit counter is provided with a synchronization signal terminal and a redundant signal terminal in addition to the digit signal terminal, and the data from the synchronization signal terminal is A data transmission system characterized in that a synchronization signal for determining the beginning of data transmission is transmitted, and a redundancy signal for distinguishing between the synchronization signal and the data signal is transmitted from the redundancy signal terminal.